PREOCUPĂRI ACTUALE PRIVIND REALIZAREA UNOR MAȘINI ELECTRICE CU DENSITATE MARE DE PUTERE PENTRU ELECTRIFICAREA SISTEMELOR DE TRANSPORT

Abstract

Applications such as the electrification of transmission systems require electric machines with high power density values. Such electric cars offer beneficial volumes and weights that are desired in transportation systems that include electric cars, electrified planes, and other types of electric vehicles.
In October 2017, the US DRIVE Group, made up of major automakers and large electricity companies, led by the U.S. Department of Energy (DOE), published a paper entitled “Research Roadmap and innovation in electrical and electronic technologies for vehicle efficiency and energy sustainability ”. This paper outlines the performance values ​​that electric traction motors must have in 2025 to accelerate the development of innovative and pre-competitive technologies to achieve a wide range of clean and efficient vehicles as well as related energy infrastructure. Thus, for electric traction motors with powers of 100 kW, used in the drive systems of single-electric vehicles, which are used in both engine and generator mode, an increase in their power density is expected. from the value of 5.7 kW / L achieved in 2020, to the value of 50 kW / L to be achieved in 2025, which means a volume reduction of 89%. This reduction in volume must be accompanied by a reduction in the cost of these engines, from $ 4.7 / kW in 2020 to $ 3.3 / kW in 2025, ie a cost reduction of 30%.

One of the factors that limit the power density of electric cars is the cooling system. In the absence of adequate cooling systems, energy losses in electric cars can cause damage to the insulation system, short circuits between the windings of the windings, demagnetization of the permanent magnets, and, finally, damage to the drive system. As a result, the analysis of ways to reduce energy losses in electric cars and the identification of efficient cooling systems are essential concerns for the realization of electric cars with high values ​​of power density.
In this paper, a presentation is made of the results of recently published research on finding constructive solutions for the realization of electric machines with very low energy losses as well as solutions for the realization of high-efficiency cooling systems, solutions that allows the performance of performance indicators for electric cars, on power density and cost, expected by the US Drive group for 2025.